title: Amnion-derived multipotent progenitor cells improve achilles tendon repair in rats.
abstract: OBJECTIVE
  Tendon injuries produce considerable morbidity, long-lasting disability, and remain a considerable challenge for clinicians and patients. The objective of the study was to assess the effect of amnion-derived multipotent progenitor (AMP) cells and amnion-derived cell cytokine solution on Achilles tendon healing by using a rat model.
  
  
  METHODS
  Achilles tendons of Sprague-Dawley rats were exposed and transected. The distal and proximal ends were injected with either saline, amnion-derived cell cytokine solution, or AMP cells in a standardized fashion and then sutured by using a Kessler technique. Tendons from each group (n = 6-13) were collected at weeks 1, 2, and 4 postoperatively and assessed for material properties (ultimate tensile strength, Young modulus, yield strength, and breaking strength). Tendons were also evaluated histologically for cross-sectional area by using hematoxylin-eosin and trichrome stains.
  
  
  RESULTS
  Mechanical testing showed that the Young modulus was significantly higher in AMP cells-treated tendons at week 4 compared with both saline-treated and amnion-derived cell cytokine solution-treated tendons. Yield strength was significantly higher in the AMP cells-treated group compared with saline-treated controls at week 4. No significant differences were observed between the study groups at weeks 1 and 2.
  
  
  CONCLUSIONS
  Amnion-derived multipotent progenitor cells have a positive effect on healing tendons by improving mechanical strength and elastic modulus during the healing process. The presented findings suggest the clinical utility of AMP cells in facilitating the healing of ruptured tendons. Both the Young modulus and yield strengths of tendons increased significantly following treatment with AMP cells.
authors.affiliation: Laboratory for Tissue Repair and Gene Therapy, Division of Plastic Surgery.
authors.forename: Justin
authors.initials: J
authors.lastname: Philip
authors.forename: Florian
authors.initials: F
authors.lastname: Hackl
authors.forename: José A
authors.initials: JA
authors.lastname: Canseco
authors.forename: Rami A
authors.initials: RA
authors.lastname: Kamel
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kiwanuka
authors.forename: Jesus Rodrigo
authors.initials: JR
authors.lastname: Diaz-Siso
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Caterson
authors.forename: Johan P E
authors.initials: JP
authors.lastname: Junker
authors.forename: Elof
authors.initials: E
authors.lastname: Eriksson